title: Exploring the determinants of fracture risk among individuals with spinal cord injury.
abstract: In this cross-sectional study, we found that areal bone mineral density (aBMD) at the knee and specific tibia bone geometry variables are associated with fragility fractures in men and women with chronic spinal cord injury (SCI).
  
  
  BACKGROUND
  Low aBMD of the hip and knee regions have been associated with fractures among individuals with chronic motor complete SCI; however, it is unclear whether these variables can be used to identify those at risk of fracture. In this cross-sectional study, we examined whether BMD and geometry measures are associated with lower extremity fragility fractures in individuals with chronic SCI.
  
  
  METHODS
  Adults with chronic [duration of injury ≥ 2 years] traumatic SCI (C1-L1 American Spinal Cord Injury Association Impairment Scale A-D) reported post injury lower extremity fragility fractures. Dual-energy X-ray absorptiometry (DXA) was used to measure aBMD of the hip, distal femur, and proximal tibia regions, while bone geometry at the tibia was assessed using peripheral quantitative computed tomography (pQCT). Logistic regression and univariate analyses were used to identify whether clinical characteristics or bone geometry variables were associated with fractures.
  
  
  RESULTS
  Seventy individuals with SCI [mean age (standard deviation [SD]), 48.8 (11.5); 20 females] reported 19 fragility fractures. Individuals without fractures had significantly greater aBMD of the hip and knee regions and indices of bone geometry. Every SD decrease in aBMD of the distal femur and proximal tibia, trabecular volumetric bone mineral density, and polar moment of inertia was associated with fracture prevalence after adjusting for motor complete injury (odds ratio ranged from 3.2 to 6.1).
  
  
  CONCLUSIONS
  Low knee aBMD and suboptimal bone geometry are significantly associated with fractures. Prospective studies are necessary to confirm the bone parameters reported to predict fracture risk in individuals with low bone mass and chronic SCI.
authors.affiliation: Department of Kinesiology, University of Waterloo, 200 University Avenue West, Waterloo, ON, Canada.
authors.forename: D
authors.initials: D
authors.lastname: Lala
authors.forename: B C
authors.initials: BC
authors.lastname: Craven
authors.forename: L
authors.initials: L
authors.lastname: Thabane
authors.forename: A
authors.initials: A
authors.lastname: Papaioannou
authors.forename: J D
authors.initials: JD
authors.lastname: Adachi
authors.forename: M R
authors.initials: MR
authors.lastname: Popovic
authors.forename: L M
authors.initials: LM
authors.lastname: Giangregorio
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D000328:Adult; D015519:Bone Density / Q000502:physiology; D003430:Cross-Sectional Studies; D005260:Female; D005269:Femur / Q000503:physiopathology; D006621:Hip Joint / Q000503:physiopathology; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D035002:Lower Extremity / Q000293:injuries; D008297:Male; D008875:Middle Aged; D058866:Osteoporotic Fractures / Q000209:etiology* / Q000503:physiopathology; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D013119:Spinal Cord Injuries / Q000150:complications* / Q000503:physiopathology; D013977:Tibia / Q000503:physiopathology